Catalytic reactor

A catalytic reactor (10) comprises a plurality of sheets (12, 13) defining flow channels (14, 18) between them. Within each flow channel (14, 18) is a foil (16, 20) of corrugated material whose surfaces are coated with catalytic material. The flow channels (14, 18) extend in transverse directions, but the foils (20) are shaped to cause the gas in those channels (18) to flow at least partly in countercurrent to the gas flowing in the other channels (14). The reactor (20) incorporates header chambers (22, 24) to supply gas mixtures to the flow channels (14, 18), each header being in the form of a cap attached to the outside of the back and covering a face of the stack. Hence different gas mixtures are supplied to the different channels (14, 18) which may be at different pressures, and the corresponding chemical reactions are also different, and heat is transferred through the sheets (12, 13) separating the adjacent channels. When the catalyst in one set of flow channels becomes spent, it can be replaced by removing a header. The reactor (10) may be used in a compact plant to perform steam/methane reforming, obtaining the necessary heat by catalytic methane combustion, and also for Fischer-Tropsch synthesis, so that the overall process involves conversion of methane to long-chain hydrocarbons.